Title: APPLICATION OF NAA AND BA IN CHEMICAL FRUIT THINNING OF ‘RED DELICIOUS’ APPLE GROUP

Authors: Milan Lukić, Slađana Marić, Ivana Glišić, Nebojša Milošević

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Abstract: The paper presents the fruit thinning response to NAA and BA plant regulators of ‘Red Delicious’ spur and standard types ‘Hapke Delicious’, ‘Scarlet Spur’ and ‘Red Chief’. The experiment was designed to evaluate NAA, over a range of concentrations 15 ppm, 20 ppm and 30 ppm when applied alone, and BA + NAA combinations (BA 60 ppm, 100 ppm, 120 ppm or 140 ppm + NAA 5 ppm) for thinning the assessed apple cultivars. All the applied treatments with NAA and BA + NAA adequately thinned ‘Hapke Delicious’ and ‘Scarlet Spur’, whereas application of NAA 20 ppm and 30 ppm and combined treatment BA 140 ppm + NAA 5 ppm were effective fruit thinners for ‘Red Chief’. In terms of the average fruit weight and number of fruits categorized as large (>70 mm or >75 mm), as well as from the aspect of fruit number per trunk cross-sectional area, the variant of treatment BA 140 ppm + NAA 5 ppm was most effective on ‘Hapke Delicious’ and ‘Red Chief, whereas BA 100 ppm + NAA 5 ppm had the best effect on ‘Scarlet Spur’.

Key words: Malus x domestica Borkh., naphthaleneacetic acid, benzyladenine, chemical fruit thinning

Title: Problems of cultivation of the newly introduced plum cultivar ‘Hanita’ into the Troyan region

Authors: Hristina Dinkova, Boryana Stefanova, Kalin Dragoyski

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Abstract: The cultivar was imported into RIMSA Troyan in 2001. It comes early into bearing, has vigorous growth, large and quality fruits. The following traits are considered as major disadvantages of the cultivar: the pronounced polarity at a young age, acute angles of growing of scaffold and semi-scaffold branches, peripheral fruiting, which in combination with its tender wood is the reason for excessive breaking of branches and alternate bearing. In order to shorten the length of scaffold branches and minimise damages caused by alternate bearing, we did some specific pruning on different dates, using a growth inhibitor (retardant) as a standard. The study inferred that the alternation of limiting pruning late winter pruning, combined with summer pruning activated fruiting buds in mid and basic part of scaffold and semi-scaffold branches, and resulted in higher yield.

Key words: plum, cultivar ‘Hanita’, growth, productivity, pruning

Title: QUALITY OF PLUM BRANDIES PRODUCED FROM PLUM CULTIVARS WITH COMBINED PROPERTIES

Authors: Branko Popović, Ninoslav Nikićević, Vele Tešević, Olga Mitrović, Miodrag Kandić, Nemanja Miletić

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Abstract: Besides plum cultivars intended for brandy making, numerous plum cultivars with combined traits are also used for the production of plum brandy in Serbia. The latter are used as dessert fruits, as well as for freezing and processing into prunes, jam, marmalade, compote, etc. In some years, depending on market trends, larger or smaller quantities of high-quality fruits of the these cultivars, which are, otherwise, intended for both fresh consumption and processing by means of different methods of preservation, are being processed into brandy. In seasons in question, plum fruits are harvested exactly at the moment when they reach the stage of maturity that is common for plums intended for processing into brandy. In this paper we investigated physical and chemical properties of fruits of five cultivars with combined traits widely grown in Serbia ‘Čačanska Lepotica’, ‘Čačanska Najbolja’, ‘Čačanska Rodna’, ‘Valjevka’ and ‘Stanley’, grown on two localities. Processing of the tested plum varieties into brandy was done in the same manner. Physical and chemical analysis was performed as well as the assessment of sensory characteristics of the produced plum brandies. Fruit characteristics of individual varieties, as well as the location from which these plum fruits originate are of great importance for the quality of brandy. The composition of produced plum brandies meets the legislation requirements of both Serbia and the EU. The utilization of high-quality fruits and applied technological processes resulted in considerably low content of undesirable components in plum brandies (methanol and prussic acid) which are below the legally permitted maximum. Differences in sensory assessment of brandies produced from the same cultivar, which depend on growing locality, ranged from 0.21 points (in ‘Čačanska Najbolja’) to 0.70 points (in ‘Čačanska Rodna’).

Key words: plum, fruit characteristics, fruit maturity, chemical composition of plum brandy, sensory characteristics of plum brandy

Title: IDENTIFICATION OF FRUIT TASTE AND ANTIOXIDANT COMPOUNDS IN WILD STRAWBERRY (F. vesca L.) AND EVERBEARING VARIETIES

Authors: Jasminka Milivojević, Jelena Dragišić Maksimović, Mihailo Nikolić, Vuk Maksimović

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Abstract: This study characterizes the fruit quality attributes and illustrates the differences in the content of tasteand some health-related compounds present in wild strawberry (Fragaria vesca L.), ‘Regina’ variety selected from the wild everbearing form of F. vesca var. semperflorens, and commercial everbearing variety ‘Irma’ bred by hybridization. ‘Regina’ yielded the highest fructose and glucose content (14,44 and 10,85 mg g-1 FW, respectively), whereas the highest content of succrose was recorded in F. vesca (19,04 mg g-1 FW). Citric acid was determined to be a major organic acid in F. vesca and ‘Regina’ (11,04 i 15,09 mg g-1 FW, respectively). However, content of citric and malic acid exhibited almost identical values in everbearing variety ‘Irma’. Among the phenolics measured, free ellagic acid was most abundant in achenes of strawberry variety ‘Regina’ (151,36 µg g-1 FW), whereas the highest amounts of pelargonidin-3-glucoside i cyanidin3-glucoside were detected in fruits of F. vesca. Similar trend was observed with total phenolic content, which expressed the highest value in achenes of strawberry variety ‘Regina’ (128,19 mg eqv. GA g-1 FW), but by analysing data obtained only for fruit flesh the highest value of total phenolics was obtained in F. vesca (10,30 mg eqv. GA g-1 FW). Accordingly, the highest level of antioxidant capacity was observed in achenes of strawberry variety ‘Regina’ (8,04 mg eqv. ask. g-1 FW), followed by fruit flesh of F. vesca (2,70 mg eqv. ask. g-1 FW).

Key words: wild strawberry, variety, sugars, acids, phenols, antioxidant capacity

Title: EFFECT OF POLYETHYLENE FOIL ON WALNUT (Juglans regia L.) GRAFTING SUCCESS UNDER STRATIFICATION CONDITIONS

Authors: Svetlana M. Paunović, Rade Miletić, Milisav Mitrović, Dragan Janković

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Abstract: The effect of polyethylene foil on walnut (Juglans regia L.) grafting success under stratification conditions was evaluated in this study involving two grafting treatments: treatment I dipping the rootstock-scion union into paraffin and stratification in sawdust up to the top of the scion, and treatment II dipping the rootstock-scion union into paraffin, stratification in sawdust up to the graft union and covering with polyethylene foil. The use of polyethylene foil induced an increase in sawdust temperature by 1 °C in 2003 and 0.5-1 °C in 2004, as compared to the treatment without the use of foil, eventually leading to a 7.7% and 8.90% increase in grafting success on day 20 and day 28 after stratification, respectively, in treatment II, as compared to treatment I.

Key words: walnut, Juglans regia L., paraffin, stratification, foil

Title: Evaluation of plum cultivars in the Troyan region

Authors: Ivan Minev, Teodora Stoyanova

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Abstract: In the past, plum was the main fruit tree species grown in Bulgaria. The plum plantations occupied the largest area in 1964. Since then until nowadays, the areas occupied by plums have decreased. In the last two decades, it has been drastic also due to the socio-economic changes. One of the reasons for the decreased production of plums is also the limited assortment of the plum cultivars. In order to enrich it, plum cultivars introduced and developed in our country were studied in the Troyan region. As a result of the study, the following cultivars were determined as suitable for growing: ‘Čačanska Lepotica’, ‘Tuleu Timpuriu’, ‘Green Gage’, ‘Gabrovska‘, ‘Mirabelle de Nancy‘, ‘Čačanska Najbolja’, ‘Tegera’, ‘Elena’, ‘Čačanska Rodna’ and ‘Jojo’.

Key words: fruit-growing, plum, cultivars, fruits

Title: Agrobiological characteristics of the plum cultivar ‘Jojo’ grown in the conditions of the Troyan region

Authors: Boryana Stefanova, Kalin Dragoyski, HristinaDinkova

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Abstract: The plum cultivar ‘Jojo’ was introduced into Bulgaria in 2003. It was grafted on the two clone rootstocks St Julien A and Fereley and studied in the Troyan region. During the past 9-year period of cultivation the trees developed normally, with more intensive growth in the first 2-3 years. They formed compact spherical crowns, well trimmed with fruit-bearing wood. In the last years, in connection with the more frequent summer droughts and non-irrigated conditions of cultivation, there was some reduction of the growth. After the beginning of its fruiting in the second year after planting and the entering into the period of full fruiting, the cultivar gave regular and high yields, but with different quality of the fruits depending on the climatic conditions. During the whole period of study no symptoms of sharka were found, either on the fruits, nor on the leaves of the cultivar. The cultivar showed resistance to most of the economically important fungal diseases of plum, but it was extraordinarily susceptible to Monilinia laxa and M. fructigena, to the same degree as ‘Stanley’. Due to its large size and attractive fruits and proved resistance to Plum pox virus (PPV), the cultivar is of interest to the farmers, particularly in regions with a high background of PPV infection.

Key words: plum, cultivar ‘Jojo’, growth, fruiting, behaviour to Plum pox